The latest uprising at the Willacy County Correctional Center began quietly on Friday morning, when prisoners refused to go to their work assignments or to breakfast. Then, inmates broke out of the massive Kevlar tents that serve as dorms. Willacy County Sheriff Larry Spence told reporters some had kitchen knives, sharpened mops and brooms. Prison officials sprayed tear gas; a SWAT team, the Texas Rangers, the FBI and the US Border Patrol all showed up. It took two days to quell the demonstration. Now administrators are beginning to transfer the 2,800 prisoners—undocumented immigrants, most serving time for low-level offenses—to other facilities, because the protest made the center “uninhabitable.”

But reports suggest that Willacy has been uninhabitable for years. This is the third disturbance at the center since the summer of 2013, when inmates protested after their complaints of broken, overflowing toilets were ignored. “I feel suffocated and trapped,” a prisoner named Dante told the American Civil Liberties Union, which released a report on conditions at the facility last year. Dante and others described the 200-man tents they were housed in as “dirty and crawling with insects…. the toilets often overflow and always smell foul.” The ACLU also found that “basic medical concerns are often ignored or inadequately addressed.” Reportedly, inadequate medical care is what sparked the weekend’s demonstrations.

The events at Willacy put a spotlight on a shadowed corner of overlap between the federal prison system, private prison companies and the nation’s immigration enforcement machinery. Willacy is one of thirteen facilities in a network of Criminal Alien Requirement (CAR) prisons under the jurisdiction of the federal Bureau of Prisons. These “second-class” prisons, run by notorious contractors like the GEO Group and Corrections Corporation of America, hold some 25,000 immigrants whose crimes largely fall into two categories: minor drug offenses and immigration infractions such as re-entering the country illegally. A decade ago the latter was rarely treated as a criminal case; as I explain in more detail here, increased prosecution of unlawful entry and re-entry has become a hallmark of President Obama’s enforcement policies. In 2013, nearly a third of all federal criminal cases related to border crossings. In Arizona, New Mexico and Texas, they represent 80 percent of the federal criminal docket.